cel light relative to idling
 

Hi everyone, I'm having a recurring problem with cel. I can drive 8 hours on the interstate with no cel. A little idling at 4-5 stoplights, I get a faint gas smell then cel.
I've replaced carbon canister, gas cap, most vacuum line, vacuum reservoir, maf sensor,check valves, both pre-cat 02 sensors, and 2 gray vac solenoids. How do I test the switch over valve w durametric. There's also a silver dollar shaped valve on the bottom side of the filler neck, what is this and how do I test it? I know some carbon canisters have one of these attached via a hose to a bottom nipple but mine only has the three connectors on top. Any help would be greatly appreciated.
Thanks again.

What codes?

Codes: P1118 P code 4 Heating power behind cat. bank 2.
P0455 P code 94-tank vent system (major leak)
P1130 P code 361 o2 sensing adaptation idle range bank 2
P1128 P code 360 o2 sensing adaptation idle range bank 1

I've replaced both precat 02 sensors, maf, charcoal canister, gas cap, vac, lines, check valves, vac reservoir, 2 gray rectangular, switches,